When modeling a loan with a floating rate, what adjustments should you include?

• A. Assume fixed rate throughout.
• B. Exclude caps because floating rates are unrestricted.
• C. Only adjust principal, not interest.
• D. Include rate index movements, caps, and potential prepayment penalties; reflect possible rate resets over time.

Answer: (D)

Floating-rate debt changes with an underlying index, so the modeling must capture how the rate evolves over time. The rate on such loans is typically the index plus a spread, and resets occur at regular dates, so you need to update the interest expense at each reset period rather than assuming a single fixed rate. Caps (limits on the maximum rate) can exist, so you must apply any rate or payment caps to keep the cash flows realistic. Prepayment penalties are also a factor if the borrower might pay off the loan early, affecting refinancing decisions and overall return. By including movements in the rate index, any caps, and potential prepayment penalties, and by reflecting rate resets over time, you produce cash flows that accurately reflect the floating-rate nature of the debt.

Locking the rate as fixed ignores the fundamental behavior of floating-rate loans. Excluding caps assumes the rate can move freely without bounds, which isn’t always true because many loans have caps or floors. Only adjusting principal would miss the core driver of costs—the interest rate itself.